The present invention relates to a coating apparatus, and particularly to an apparatus for coating strip material. More particularly, the present invention relates to a liquid coating material usage detector in a metal strip coating apparatus.
Coating apparatus are configured to apply a coating onto material. See, for example, U.S. Pat. No. 6,013,312 to Cornell et al., U.S. Pat. No. 5,985,028 to Cornell et al., U.S. Pat. No. 5,549,752 to Hahn et al., and U.S. Pat. No. 4,604,300 to Keys et al.
A coating apparatus includes a coater configured to dispense liquid coating material onto a moving strip of material, a supply unit containing liquid coating material to be dispensed to the coater, a reservoir positioned to receive liquid coating material dispensed from the supply unit, and a liquid meter unit including a flow passage and a flow regulator associated with the flow passage. The coating apparatus further includes flow rate manager means for supplying liquid coating material to be dispensed to the reservoir to fill the reservoir to a desired level and for changing a flow rate of liquid coating material discharged from the liquid meter unit to the coater to match a predetermined flow rate specification by determining the flow rate of liquid coating material passing through the flow passage formed in the liquid meter unit and operating the flow regulator to regulate the flow rate of liquid coating material discharged to the coater.
In preferred embodiments, the flow rate manager means includes a proximity sensor which cooperates with the reservoir to detect the flow rate of the liquid coating material. The reservoir is cylinder-shaped and is formed to include an opening at its upper end, a coating material inlet, and a coating material outlet. The supply unit fills the reservoir with liquid coating material intermittently through the coating material inlet. When the liquid coating material in the reservoir reaches an upper level, the supply unit ceases filling the reservoir to begin the process of measuring the flow rate.
The sensor is mounted to the upper end of the reservoir and sends a first signal through the opening of the reservoir to sense a decreasing level of liquid coating material in the reservoir as the liquid coating material discharges from the reservoir through the coating material outlet. The sensor provides a second signal indicative thereof to the controller. The controller determines the flow rate of the liquid coating material based on the second signal. The inside diameter of the reservoir is small enough to provide sufficient resolution of changes in the level of the liquid coating material in the reservoir.
Additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the invention.